Dementia of Alzheimer's type (DAT) occurs in middle and late life. The natural history and the risk factors of DAT remain undefined. The putative genetic and molecular mechanisms are the object of active investigations. It is conceivable that several etiologies are involved in DAT. Detailed examination of the brain is essential not only for clinico- pathological correlations but also for defining whether specific neuropathologic phenotypes can be correlated with sub-groups of Alzheimer patients. By defining putative neuropathologic phenotypes, the neuropathologist may contribute to the development of the genetic analysis. The autopsy is a fundamental task of the Neuropathology Core or the Alzheimer Disease Core Center. The brain will be obtained and, when possible, the complete autopsy will be performed. Brain tissue will be used for neuropathologic, immunohistochemical, image analysis studies, as well as for neurochemical and molecular biological investigations. Accurate morphologic studies will be carried out and the results correlated with clinical, neuropsychological, and brain imaging data. Furthermore, well-characterized brain tissue will be available for morphological, neurochemical, and molecular research projects. The Neuropathology Core will provide opportunities for developing and sharing the resources that are essential for a better understanding of lesions, pathogenetic mechanisms, and etiological factors of Alzheimer's Disease.